[Beowulf] MPI ABI

> The government is one of the few forces that could mandate a proper MPI
> ABI at this point in time;
They certainly aren't the only ones -- vendors of proprietary
applications that use MPI plus vendors of interconnect hardware get
significant benefits from an ABI.
Anyone who wants to distribute binaries of open-source MPI apps would
also benefit, but they generally don't get to use the verb "mandate".
-- greg